Instructional Services

BMI

Body Mass Index (BMI)

Body Mass
Index is a weight for stature index that can be utilized in conjunction with
other health profile traits to indicate possible risk for disease. Because the percentage of body fat changes
during the growing years, children and teens require adaptation of the BMI
results to reflect this. The Body Mass
Index Percentile identifies the place on the growth charts where a particular
student compares with other students of the same gender and age.

The Centers for Disease Control and Prevention have
suggested that Body Mass Index percentiles less than 5% and more than
85% may represent risk to health.

Neither
the BMI nor the BMI% is a diagnostic tool.
The student’s health care provider is the person most qualified to
evaluate your student’s measurements in conjunction with the child’s other
health profile traits and to make recommendations for addressing health risks
if they exist.

For more
information on Body Mass Index and health, log on to the web site for the
Centers for Disease Control and Prevention, US Department of Health and Human Services
at www.cdc.gov/growthcharts.

What is a BMI percentile?

After BMI is calculated for children
and teens, the BMI number is plotted on the CDC BMI-for-age growth charts (for
either girls or boys) to obtain a percentile ranking. Percentiles are the most
commonly used indicator to assess the size and growth patterns of individual
children in the United States. The percentile indicates the relative position
of the child's BMI number among children of the same sex and age. The growth
charts show the weight status categories used with children and teens
(underweight, healthy weight, overweight, and obese).

BMI-for-age weight status categories
and the corresponding percentiles are shown in the following table.

Weight
Status Category

Percentile
Range

Underweight

Less than the 5th percentile

Healthy weight

5th percentile to less than the
85th percentile

Overweight

85th to less than the 95th
percentile

Obese

Equal to or greater than the 95th
percentile

How
is BMI used with children and teens?

BMI is used as a screening tool to
identify possible weight problems for children. CDC and the American Academy of
Pediatrics (AAP) recommend the use of BMI to screen for overweight and obesity
in children beginning at 2 years old.

For children, BMI is used to screen
for obesity, overweight, healthy weight, or underweight. However, BMI is not a
diagnostic tool. For example, a child may have a high BMI for age and sex, but
to determine if excess fat is a problem, a health care provider would need to
perform further assessments. These assessments might include skinfold thickness
measurements, evaluations of diet, physical activity, family history, and other
appropriate health screenings.